All Questions
18,606
questions
2
votes
0
answers
28
views
How do Inertial Navigation Systems compensate for their inability to measure gravitational acceleration?
Inertial Navigation Systems use Inertial Measurement Units (IMUs) to sense acceleration. Essential components of IMUs include triads of
• Accelerometers to measure linear acceleration
• ...
- 17.6k
9
votes
1
answer
818
views
Are there multiple types of UTC time?
I have been checking in detail the specifications of RINEX navigation files version 3.05, and something in the definition of the header of these navigation files caught my attention.
One of the lines ...
- 1,636
-3
votes
0
answers
107
views
Can liquid mercury be used as a reusable rocket fuel? [closed]
If liquid Mercury is changed into solid Mercury thus generating energy and specific impulse why can I not then re-use the solid Mercury as a fuel?
1
vote
0
answers
93
views
Objects move clockwise instead of counter-clockwise
I'm trying to write an orbital simulation with patched conics. For my sources I'm using https://orbital-mechanics.space/ and Fundamentals of Astrodynamics (Second Edition).
Both sources suggest to use ...
- 63
9
votes
1
answer
182
views
Using today's technology, is interstellar navigation possible?
I was watching this video essay discussion about space elevators, and on a bit of a tangent, the physicist talks about difficulties with interstellar missions, specifically comments about navigation ...
- 17.9k
4
votes
1
answer
177
views
How beaten up would Voyager 1 be in 40,000 years?
How much damage would there be, both physically and to the computers, memory etc, upon arrival to Gliese 445 in 40k years by radiation and interstellar debris?
user52823
3
votes
3
answers
134
views
Is it easier to detect a satellite than an aircraft with a land-based radar?
I am suspecting that it is easier to detect a satellite because in the space, there is no other thing. In other words, the background is cleaner.
Is it right?
- 173
3
votes
1
answer
327
views
Creating an animation short and need orientation info
I'm creating a short film celebrating Voyager 1's progress out of our Solar home. I would like to be as accurate as possible.
Question: What is the craft's normal orientation as it travels? Is the ...
user52823
3
votes
1
answer
135
views
Does a country need to announce the parameters of its newly launched satellite to the world?
I am wondering if there is any international organization regulating such things.
Possibly countries do not need to tell anything about their spy satellites, but should tell about their commercial ...
- 173
3
votes
2
answers
113
views
sun pointing coordinate system design
I am trying to program slew maneuver procedure for a spacecraft. My goal is to define a target coordinate system that is aligned with sun vector so that the spacecraft can slew its attitude to always ...
- 31
3
votes
1
answer
2k
views
Space craft and interstellar objects
How do the Voyager Spacecrafts avoid crashing into objects in interstellar space?
2
votes
0
answers
40
views
NASA’s NIAC has awarded phase III funding for Diffractive Solar Sails. Demonstration mission in the works?
Diffractive lightsails use small gratings embedded in thin films to produce diffraction (which causes light to spread out when it passes through a narrow opening).
Diffractive light sails are a ...
- 17.6k
19
votes
7
answers
9k
views
What kept the Soviets from going to the Moon (before the US)?
I know that Saturn V's payload was 140 tons, about 20 times that of Soyuz. The Soviets did not have a functioning rocket with similar characteristics. But why? They had a head start in the space race ...
- 412
4
votes
1
answer
1k
views
Is this 62 mile interception altitude reasonable for this stated missile trajectory?
If a missile is launched from Yemen, and destined for Israel which is "nearly 1,000" (less than) miles away, is it likely for that missile to be intercepted at 62 miles of altitude? Where on ...
- 435
0
votes
1
answer
84
views
Slowing down 16 Psyche using an enormous solar sail to reach the inner planets
I am writing a sci-fi story and would like my science as hard as possible.
I was thinking of using the solar sail as a kind of sea anchor. Slowing down, the asteroid would move down to the inner ...
3
votes
0
answers
177
views
Why did Starship start tilting to one side as soon as it lifted off during IFT-2?
I've noticed that no one has talked about this, making me think that maybe it's normal or expected as a way to veer off the launch pad to protect stage 0 equipment. However, no matter how many times I ...
- 191
0
votes
0
answers
34
views
Is mandatory to coat SLV fairing with anti static paint, please? [closed]
What type of surface coatings are required for payload fairing? Fairing
- 1
5
votes
2
answers
963
views
Object slowest at periapsis - despite correct position calculation
I'm coding up a simulation of celestial bodies using patched conics. At the moment I'm stuck with calculating the velocity of the object in the perifocal frame.
For the position I'm simply using the ...
- 63
-3
votes
1
answer
102
views
Artifical Gravity central core [duplicate]
so have read about the centrifugal acceleration to create artificial gravity. Being mindful of the limitations of getting objects into space, the question is more curiosity. Is it possible to work ...
1
vote
0
answers
63
views
What kind of propulsion did/does the Raytheon EKV vehicle use?
Raytheon has developed an Exoatmospheric Kill Vehicle, designed to intercept an ICBM and destroy it through a collision. Here are some related links:
Wikipedia page
YouTube video about the project, ...
- 1,174
2
votes
2
answers
124
views
What is ascent venting?
I am writing a report on CubeSat construction, and while reading Cal Poly's CDS I encountered the concept of ascent venting (or more specifically, the constraint that 'ascent venting per ventable ...
- 23
-1
votes
0
answers
73
views
How does the Falcon 9 first stage navigate to and precisely land on the drone barge? [duplicate]
Actually, I have the same question about landing back at the launch site on solid ground.
The landing site is at a fixed position, so I would think inertial guidance and/or GPS would get the booster ...
- 995
3
votes
2
answers
103
views
Typical external temperature profile for a LEO satellite
I bumped into a question regarding LEO orbit.
Is an external temperature profile available in literature as a first approximation for thermal analysis? I bumped into articles mentioning that the ...
- 31
1
vote
0
answers
55
views
Visualization tool for Space Rendezvous and docking [closed]
How to make the 3D visualization the space rendezvous and docking missions once I have the data log of the operation from mathematical simulation. I found some potential tools such as SPICE and Free ...
- 11
5
votes
2
answers
234
views
Is a brachistochrone the best ascent profile?
I just watched Neil Tyson say the brachistochrone path discovered by the Bernoulli bros is the best ascent profile for an ascending rocket. Link
I hadn't heard this before. Is this really a thing? Or ...
- 15.6k
0
votes
0
answers
32
views
Eclipse/sunlight detection for LEO satellites
I am trying to use poliastro to obtain the positions of the propagated spacecraft and the lighting conditions at each position.
The documentation in poliastro page shows an example of the shadow ...
- 173
2
votes
1
answer
94
views
Is vacuum created between the inner engines under Earth's atmosphere that could affect the booster in the early moments of the ascent?
The booster has a lot more engines than the Starship.
My thoughts are that if there's isn't a pressure relief to the innermost engines they could create a vacuum pulling the hot gasses expelled. I ...
- 21
10
votes
2
answers
2k
views
Wouldn’t Super Heavy flip following stage seperation, even without help from its 3 lit engines?
At 1:40 on the SpaceX launch commentary, the announcer said that after hot staging, “the three engines still firing on Super Heavy will flip the booster around”.
With empty tanks, the center of mass ...
- 17.6k
0
votes
0
answers
57
views
Impact of Satellite Movement on Signal Processing Between Tx and Rx:
I am researching how the movement of satellites affects signal processing between a transmitter (Tx) and receiver (Rx). Satellites can function as either transmitters or receivers.
The movement will ...
- 91
1
vote
1
answer
167
views
During Starship's recent flight, the stack appeared to be venting gas during the staging sequence. What was it?
During Starship's launch on November 18, 2023, the two stages successfully executed hot staging and separated from each other. In the seconds leading up to ignition of the upper stage engines, the ...
- 995
18
votes
1
answer
5k
views
Person falling from space
A person at rest 500 km above the Earth falls straight downwards. She has a snug magical force field around her that is totally rigid and completely protects her from outside heat. The force field ...
- 199
1
vote
0
answers
109
views
Scattering of exhaust gases during Starship IFT-2 hot staging
Various footage of the IFT-2 of SpaceX's Starship show intriguing pattern of, presumably, exhaust gases illuminated by the Ship's 3+3 engines (attached below). While this may be an optical illusion, ...
- 111
4
votes
1
answer
262
views
Why Spacex Starship is not a modular rocket?
The past Nov 18 was the last launch, of Starship.
The things didn't happen as planned.
But all of us know that soon or later Spacex will make it a successful.
It will be a long time before it can be ...
- 141
2
votes
0
answers
232
views
Why did Starship perform an abrupt course correction seconds before stage separation?
During Starship second integrated test flight IFT-2
There is a seemingly rapid attitude change seconds before stage separation, the whole vehicle making a turn towards the right of the image.
What is ...
- 4,218
6
votes
1
answer
774
views
What are these "fountains" during the deluge for the Super Heavy launch?
Below I've circled (in yellow) what looks like two fountains just before the Super Heavy launch. They start at T-5 seconds, just a fraction of a second before the water deluge can be seen on the ...
- 836
23
votes
3
answers
4k
views
Was Starship’s “launch window” administrative, rather than due to orbital mechanics?
According to Wikipedia,
a launch window is the time period on a given day during which a
particular rocket must be launched in order to reach its intended
target.
SpaceX’s internet launch coverage ...
- 17.6k
6
votes
1
answer
2k
views
Did Starship Ship 25 burn up on re-entry?
SpaceX Starship Ship 25 launched and managed a successful separation from the booster and reportedly made it into space before the autonomous flight termination system activated, destroying the ...
- 744
2
votes
3
answers
188
views
Disposing of Obsolete Satellites by Propelling to the Sun
I'm not scientifically adept, so bear with me. Would it be feasible to retain enough fuel on new satellites/space stations, etc., that we could dispose of them when obsolete by sending them to the ...
Jim Elmore
3
votes
0
answers
92
views
How much lead (kg) would you need to survive for an extended period of time in Jupiter’s radiation belts?
Imagine you have a 1 by 1 by 2 meter chamber that a human needs to survive in for one year, while orbiting in Jupiter’s radiation belts. How much lead, in weight, would have to surround the chamber to ...
- 31
2
votes
3
answers
790
views
(How) would the water deluge system impact Starship superheavy captures?
(How) would the water deluge system impact Starship superheavy captures, when they eventually manage to return to starbase?
Could it be turned on during landing attempts? Would that reduce lift (...
4
votes
2
answers
229
views
Does swimming experience help to adapt to weightlessness?
In the story I currently write, I have a character who has been a passionate swimmer for decades. Now, she goes to space. I wonder how she would adapt to weightlessness, and would her swimming ...
2
votes
0
answers
35
views
Nozzle contour estimation (Merlin 1D Vacuum)
I would like to run a fluid simulation of the diverging section of a Merlin 1D Vacuum engine. While most relevant parameters (such as expansion ratio, flow rate, and nozzle area) are readily available,...
- 149
2
votes
1
answer
112
views
How does SpaceX get its boosters from the ASDS to SLC-40?
Getting a freshly-landed booster from a drone ship to pad 39A seems straightforward: there's a deepwater channel from Port Canaveral to a dock next to the VAB. Sail the ASDS up, lift the booster off ...
- 14.6k
4
votes
2
answers
451
views
Are rockets deliberately throttled back towards the end of the burn to spare crew and airframe g-forces?
Throughout its burn, a rocket gets lighter as propellant is consumed. As a result, acceleration (and g-force) increase. In the shuttle, the SSMEs were throttled back towards the end of the burn ...
- 17.6k
0
votes
0
answers
88
views
Can coking be avoided by pumping fuel after shutdown?
As I understand it, coking in kerolox engines occurs when the engine shuts down and fuel flow stops, causing fuel still in the coolant channels to overheat and decompose.
Can this problem.be avoided ...
- 2,645
1
vote
0
answers
31
views
Definition of "elevation mask" when it comes to sensors and ground stations?
My understanding is that elevation mask is a term for purposely limiting sensor observations, usually on the ground, by intentionally blocking sky observations from the horizon to a specific elevation....
- 21
2
votes
1
answer
172
views
On space stations, what do they do with small solid particles which are free floating?
I heard a claim that a piece of graphite, of half a millimeter size which broke from a pencil can kill a person who inhales it. Is this a major problem or an exaggeration? In a gravitational ...
- 3,117
4
votes
0
answers
86
views
Do ISS astronauts have a preference for when EVA tasks are scheduled with respect to lighting conditions?
Given the choice, do ISS astronauts prefer to schedule EVA tasks on the “day light” side of the ISS, the “shadow" side of the ISS or in the shadow of Earth’s night side?
I suspect the intense, ...
- 17.6k
3
votes
0
answers
71
views
Have spherical dish antennae been used with Molniya satellites to avoid switch-over signal loss?
Molniya-orbit communication satellites work well for ground locations near the poles. These high eccentricity, highly inclined orbits, with a period of 12 hours, “loiter” for about 6 hours over the ...
- 17.6k
9
votes
2
answers
3k
views
Term for deformation due to gravity
In this video,
If you look closely, you can see the smaller planet deforming before the actual collision. I think I remember a term existed for this. I think it is ...
- 99